Leopoldo O'Donnell (lāōpōl´dō ōŧħō´nĕl), 1809–67, Spanish general and statesman; member of a branch of the Irish O'Donnells of Tyrconnel. He fought successfully for Isabella II against the Carlists. When Espartero seized (1840) power in Spain, O'Donnell went into exile with Maria Christina. He failed in an attempted coup against Espartero in 1841. After Espartero's fall, O'Donnell was governor of Cuba (1844–48). In 1854 he led a military revolt and, assisted by a popular uprising in Madrid, overthrew the government of Maria Christina. He then served as war minister under Espartero, whom he ousted (1856), and was several times premier (1856, 1858–63, 1865–66). As the leader of the Liberal Union party, which he had founded, O'Donnell followed a more or less moderate policy. He took command in the successful Spanish campaign (1859–60) in Morocco and after the capture of Tétouan (Span. Tetuán) was given the title duque de Tetuán. In 1866 his harsh repression of an uprising organized by Gen. Juan Prim led to O'Donnell's dismissal.